Tool for cutting circular holes



April 8, 1952 L. MASINI TOOL. FOR CUTTING CIRCULAR HOLES Filed May 51,1951 A 011/5 MAS/Afl- Attorney Patented Apr. 8, 1952 UNITED STATESPATENT OFFICE 2,591,8475

TOOL FOR CUTTING CIRCULAR HOLES Louis Masini, Highwood, Ill. IApplication May 31, 1951, Serial No. 229,048

6 Claims.

i This invention relates to a novel tool or'implement adapted to beapplied to and form an attachment for a conventional drill bit forcutting circular holes of different diameters, larger than the diameterof the drill bit and which is capable of cutting a circular hole of adiameter only slightly greater than the diameter of the drill bit;

a circular hole cutting attachment for drill bits capablezoflbeing usedin drill bits of. different diameters and of different lengths andincluding cutting elements having blades of different lengths capable ofbeing selectively positioned for use with a drill bit, depending uponthe thickness of a workpiece in which a circular opening is to be cut.

Various other objects and advantages of the invention will hereinafterbecome more fully apparent from the following description of thedrawing, illustrating a presently preferred embodiment thereof, andwherein:

Figure 1 is 'a side elevatidnal view of the invention;

Figure 2 is an end elevational view thereof looking from right to leftof Figure 1;

--Figure 3 is a top plan view thereof;

Figure 4 is a longitudinal sectional view taken substantially along aplane as indicated by the line 4-4 of Figure 3, and

Figure 5 is a cross sectional view taken substantially along a plane asindicated by the line 5-75 of Figure l.

The circular hole cutting attachment in its entirety is designatedgenerally I and includes a rod 80f circular cross section which isthreaded from end-to-end thereof and which is provided adjacent one endwith a bore 9 extending diadf said rod." The inner end of one bore l2opens into the intermediate portion of the bar Band.

threaded into the bore l2 toward the diametrical bore 9, disposedadjacent, thereto, and has a restricted unthreaded shank portion l4 atits inner end. The outer end of the retaining screw I3 is provided witha kerf l5. A jamb nut I5 is mounted on the screw l3 beyond the adjacentend ofstherrod 8 to retain the screw I3 in an adjusted position. Acorresponding screw Ip3aismounted in the other threaded bore l2 andlikewise carries a jamb nut Ilia.

.With the screw I3-backed off, a drill bit 18 is inserted through thebore 9, said bit l8 being of proper size to fitvrelatively snug in thebore 9. The screw I3 is then advanced inwardly sothat its restrictedshank [4 will seat in a flute groove of the bit 18 to clamp-the bit inthe bore and diametrically of the rod 8 and the jamb nut i6 is thenadvancedtoretain the screw 13in an advanced position. Beforevapplication of. thebit l8 to the bore 9, a nut l9, washer 20 andcutting implement, designated generally 2|, is applied to the rod 8 andpositioned to the left of the bore 9, as seen in Figures 1, 3 and 4. Thenut I9 is threaded on the radii and the washer20 isdisposed. between thenut l9 and cutting unit 2! and said cutting unit 2| is disposed betweenthe washer and bore 9 and accordingly between said washer andthe bit 18,after application of the bit. The washer 20 is provided-with a tongue 22which extendsinto the'opening thereof and which slidably engages thegrooveor channel I I for nonrotatably mounting the washer 20 on therod8. The cutting unit 2| includes an annular hub 23 which is turnablydisposed on the rod 8 1 andwhich has three cutting blades 24, 25 and .26extendingradially from thehub 23 and which edge of the blade disposed"at a right angle to said aforementioned outer side.

A sleeve-30 is provided with a bore sized to slidably engage on the rod8 and is insertable .thereon'from the right-hand end of the rod. The

sleeve 39 is provided with diametrically aligned notches 31 which extendlongitudinally thereof from adjacent its right-hand end and which open?between the cutting unit 2la and nut I911.

outwardly of its left-hand end. The notches 3| are of a width slightlygreater than the diameter of the bit I8 so that portions of the bitextend through said notches and to permit the sleeve 38 to sliderelatively to the bit I8 and to be-positioned on the rod 8 with the endsof the sleeve 30 disposed on opposite sides of the bit I8. As seen inFigures 3 and 4, each of the notches 3| is of a length at least equal tothe diameter of the bit I8 plus the thickness of the nut I9 and washer20. A nut 32 is threaded onto the rod 8 to the right of the sleeve 38and a split lock washer 33 is mounted on the rod 8 between the sleeve 30and nut 32.

A nut I9a, washer 20a and cutting unit 2Ia is applied to the otherleft-hand end of the rod 8 and displaced to the right beyond the boreI0, said parts corresponding to the nut I9, washer 28 and cutting unit 2I, respectively, with the exception that the blades of the cutting unit2I in addition to being of different lengths relatively to one anothermay likewise be of different lengths as compared to the lengths of theblades of the cutting unit 2 I.' A drill bit I8a of a proper diameter tosnugly engage the bore II] is applied to said bore and is secured inadjusted positions therein by advancing the retaining screw I3a,

aspreviously described in reference to the screw I3, so that therestricted screw shank I40: will engage tight in a flute groove of thebit I811. The cutting unit 2Ia is disposed between the washer 28a andthe bit I8a and said washer is disposed A sleeve 30a, shorter than thesleeve 38, is mounted on the rod 8 and is applied thereto from the leftendof the rod and has diametrically aligned notches 3Ia which openoutwardly of its inner end and which are each of a width to receive thebit IBa and of a length no greater than the diameter of the bit. A nut32a is threaded onto the rod 8 to the left of the sleeve 38a and awasher 33a, corresponding to the washer 33, is disposed on the rod 8between the sleeve 38a and nut 32a. V 1

It is to be understood that when the bit I8 is utilized it is employedwith the parts disposed adjacent thereto and the bit I8a is removedtogether with the parts located adjacent said bit IBa. The upper shankend of the bit I8 is secured in a drill chuck I! which may form a partof a drill press, not shown, and the jaws of the drill chuck may extenddownwardly to and abut against the upper portion of the sleeve 38 andwill not interfere with the cutting unit 2| since one of the bladesthereof will be extending downwardly, for example the blade 24, and theother two blades thereof will be projecting outwardly and upwardly at anincline and will be so disposed as not to interfere with or be engagedby the chuck I I. By tightening the nuts I9 and 32; the cutting blade 24which is disposed in an operative position below the rod 8 will beretainedat a predetermined distance radially from the axis of the bit I8and will be held against swinging relatively to the rod 8 by the sleeve30 and the lock washer 28, as the former is retained against rotation onthe rod 8 by the bit I8 engaging its notches 3I while the latter is heldnonrotatably on the rod 8 by its tongue 22 engaging in the groove orchannel H. Assuming that a, piece of material, not shown, is disposedbee low the bit I8 clamped to a supporting surface such as, a. drillpress table, not shown, as the bit I8. is revolved and displaceddownwardly by operation of the drill press or other machine or 4implement to which the chuck I1 is attached, the drill !8 will initiallybore a hole into the work after which the point 29 of the blade 24 willmove into contact with the work and execute a circular cut therein aboutthe axis of the drill bit I8 as a center for cutting a circular holethrough a workpiece of a diameter substantially greater than thediameter of the drill bit I8. It will be readily apparent that thediameter of the hole thus cut may be enlarged by loosening the nut I9and advancing the nut 32 from right to left until the bit I8 engages theinner ends of the notches 3|, or the nut 32 may be backed off from leftto right and the nut I8 advanced in the same direction up to the limitwhere the hub 23 abuts the bit I8 for reducing the diameter of the holecut by the bit I8 and cutting unit 2I.

Similarly, the bit I8a may be employed with the parts shown at theleft-hand end of the rod 3 and with the chuck I'I applied to the uppershank end of the bit IBa and in which case the bit I8 and the partsassociated therewith and mounted on the right-hand end of the rod 8 areomitted. The bit I8a and its associated parts are employed for cuttingonly very small holes of the diameter of the bit I8a plus twice thethickness of the cutting unit "2Ia and measured radially from the bitI8a, since the notches 3Ia are each of a length only equal to thediameter of the bit IBa so that the inner end of the sleeve 38a isincapable of projecting to the right beyond the bit Isa and thereforecannot space the cutter 2Ia from said bit. However, such spacing may beaccomplished by inserting additional washers 28a between the right-handend of the sleeve 30a and the cutting unit 2 Ia. Similarly. the cutter2I may be spaced a greater distance from the bit [8 than is provided forby the notches 3| of the sleeve 38 by inserting additional washers 28between the cutting unit 2I and the left-hand end of the sleeve 38.

The cutting units 2I and 2 Ia are provided with blades of differentlengths for use in cutting through workpieces of different thicknessesand in each instance the point of the blade employed is disposed abovethe level of the leading, lower end of the bit so that the bit mayinitially be started in the work before the blade commences to executeits circular cutting operation.

While the bit I8 is anchored in the rod 8 normally only by the retainingscrew I3, unless the sleeve 30 is moved to the left as far as possible,the bit Isa is anchored not only by the screw I3a but additionally bythe sleeve 30a which is held in gripping engagement therewith by the nut32a, and washer 33a.

' It is also possible to out very large holes with either bit byomitting the cutting unit normally associated therewith and by utilizingthe cutting unit and associated parts of the other bit but with theother bit removed. The boring of large holes can also be accomplished byremoving the unit at the right-hand end of rod 8 (Figures 1, 2 and 3)except the nut 32 and washer 20, and then repositioning the parts sothat the nut I9a will be to the left of the bit I8a and sleeve 30a, thecutting unit 2Ia, being located between the nuts I8a and 32 and to theright of nut I8a, and the washers 20a and 28 being disposed between thecutting unit 2 Ia and the nuts Ifia and 32, respectively.

Various modifications and changes are contemplated and may obviously beresorted to, with out departing from the spirit or scopeof the inventionas hereinafter defined by the appended claims.

I claim as my invention:

1. A circular hole cutting attachment for drill bits comprising a rod ofcircular cross section externally threaded from end-to-end thereofhaving a bore extending diametrically there through adjacent one of itsends and a longitudinally extending threaded bore opening outwardly ofsaid end and into said diametrical bore, said diametrical here beingadapted to detachably receive and snugly engage a portion of a drillbit, a retaining screw threadedly engaging said threaded bore and havinga restricted inner end adapted to engage in a flute groove of the bitfor detachably securing the rod rigidly to the :bit, a sleeve slidablymounted on the rod having diametrically aligned longitudinally extendingnotches opening outwardly of one end of the sleeve adapted toaccommodate portions of the drill bit, a pair of nuts threadedlyengaging said 'rod beyond the ends of the sleeve, a washer slidablymounted on the rod between one of the nuts and the adjacent sleeve end,a lock washer mounted on the rod between the opposite end of the sleeveand the other nut, and a cutting unit having an annular hub slidablymounted on the rod between the first mentioned end of the sleeve and thefirst mentioned washer, said cutting unit having a blade projecting fromthe hub provided with a cutting portion at its outer end adapted tocooperate with a leading end of the bit for cutting a circular openingand terminating nearer the axis of the rod than the leading bit end.

2. A cutting attachment as in claim 1, said notches of the sleeve eachbeing of a length substantially greater than the diameter of the drillbit 3. A cutting attachment as in claim 1, said notches of the sleeveeach being of a length no greater than the diameter of the drill bit.

4. A cutting attachment as in claim 1, said rod having a grooveextending from end-to-end thereof, said first mentioned washer beingprovided with a tongue extending into the opening thereof, said tongueslidably engaging the rod groove for nonrotatably mounting thewasher onthe rod.

5. A circular cutter attachment as in claim 1, and a jarnb nutthreadedly engaging the exposed end of the retaining screw and abuttingthe end of the rod from which said screw projects for retaining theinner end of the screw in engagement with the drill bit.

6. A circular cutting attachment asin claim 1, said cutting unitincluding a plurality of blades projecting radially from the hub andequally spaced from one another circumferentially of the hub, saidblades being of different lengths and each' having a cutting portion atits outer end, said cutting portions being spaced different distancesfrom the axis of the hub.

LOUIS MASINI. No references cited.

